Method of and apparatus for altering the condition of gases.



K. AHLQUIST. METHOD, OF AND APPARATUS FOR ALTBRING THE CONDITION OF G LSES.

AEILIGAT ION IILBIJ 19318.17, 1906. l

Patented NOV.14,1911Q Winesses:

uis45 UNITED STATE'I O FFICE.

KARL AHL QUIST, OF RUGBY, ENGLAND.'ASSIG-NOR TO GENERAL E1 .ECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD OF AND APPARATUS FOR ALTERING THE CONDITIXN 0F GASES.

To all whom it may concern:

Be it known that I, .KARL AHLQUIST, a subject of the King of Sweden, residing at- ].47 Clifton road, Rugby, England, have in- ..vented certain new and useful Improvements particularly for use in connection with elastic fluid turbines. The invention is, however, not limited to turbines; it may also be used for the purpose of increasing the pres sure of gases Whether obtained as above in dicated or otherwise.

My invention consists in causing the gas at a suitable pressure to expand so as to increase its kinetic energy by a desired amount and in utilizing more or less of this kinetic energy to produce recompression of the gas, the gas be ore and during compression being cooled in any suitable manner.

My invention further consists in an apparatus for carrying the method intg effect.

In the accompanying drawing whichserves to illustrate my invention, Figure 1 is a sectional elevation of a single nozzle for transforming the energy of a gas supplied to a rotary engine, and F ig, 2 is a sectional view of a number of such nozzles arranged to form a compressor; I

In oarryin my invention into efiect according to t e embodiment illustrated in i Fig. 1, I provide a direct nozzle 01' nozzle portion which has a small inlet opening 1 and expands gradually therefrom into a practically cylindrical region 2 and a reversed nozzle or nozzle portion that gradusuitable manner. formed with hollow Walls containlng pasally contracts from the region 2 toward the outlet 3. The contracting and practically cylindrical sections of the nozzle are arranged so that they-can be cooled in any For example they maybe sa es 4' through which a suitable cooling fluid such as water maybe circulated. The gas to bedealt with enters the throat I of the divergent portion of the direct nozzle and expands int-his portion so as to reduce its pressure and. increase its kinetic energy in a well understood manner. It is then Specification of Letters Patent.

Application filed February 17, 1906.

Patent (l Nov. 14, 1911.

Serial No. 301,801.

cooled in the cylindric Ll portion 2 of the nozzle and during its passage through the com'ergent portion of he reversed nozzle. During the passage through the cylindrical portion 2 the volume 0: the gas diminishes due to the heat abstracxad but .the velocity of the particles is not interfered with. Owing to this cooling :1] d consequent reduction in volume in the (ylindrical and convergent portions of th nozzle less kinetic energy is required to cc mpress the gas to a givenpressure in said convergent portion of the nozzle than. it would otherwise be necessary to expend. C( nsequently the pres sure of the gas can be 1 aised by a complete utilization of the kinetic energy, so that it issues from the throat l of the convergent part of the nozzle at a maximum pressure above its original pressur Or it may be co1npressed in the convergel' t part of the nozzle to a given pressure less thansaid maximum pressure by a partial util ization of the kinetic energy and will then hr ve more kinetic en ergy than it would have had b expansion to the same pressure in a simpl nozzle. In the first care,- where the whole of the kinetic energy developed in the expanding and cylindric il portions of the nozzle transformed'l ack to pressure assuming frictionless n10 :ion, the apparatus acts as a compressor, and if a number of such nozzles are connect (1 in series as shown in Fig. 2 with interveni ng reheating chain hers into which the ga ies from each nozzle enter and from which they pass into the succeeding nozzle a stag: compressor will be formed by means of which the pressure of a gas may be raised b1 a desired amount. In the case, however, in which only a art of the kinetic energy of the gas is trans ormed back to pressure, the rnnaining energy of the g'as may be used fcr reducing motive power, for example, by riving a turbine wheel as illustrated in I 1g 1, the gas issuing from the nozzle on'to tl e wheel I In the operation of ga s turbines the gas or fluid has usually to be d1 livered to the wheel at a high temperature which may be above that which the material of which the wheel is formed can withstand According 'to the present invention the temperature ofth'e s or fluid may be lowei ed very materia ly Without reducing the k netic energy of the e diver ent be increased, if the friction in the cylindrical and converging parts of the nozzle is not so great as to absorb the gain in energy.

The main essential in the application of the invention to turbines is to cause the gas to expand in the divergent portion of the nozzle to a pressure' .belo w the pressure in the turbine. The expanding portion of the nozzle is provided with a lining 7 preferably of some refractory material. As much heat as is convenient is then abstracted and the gas allowed to compress to the desired pressure with. further abstraction of heat in the convergent portion of the nozzle.

It will be obvious that the shape of the nozzle may be varied in different Ways for producing the results above mentioned witl1- out departing from the spirit of the invention.

From the foregoing it will be seen that a direct nozzle is provided for cbnverting pressure into velocity, and a second or reversed nozzle properly shaped which re,- ce-ives' fluid at high velocity from the direct nozzle and converts the velocity into pressure. Between the direct and reversed nozzles is ameans for coolin the fluid after it has passed through the irect nozzle. The entrance to the direct nozzle should be well rounded because the fluid expands while passing through it, as it also does in the expending portion beyond. Insome cases the nozzle should have the walls leading up to the throat -the point of greatest restriction,convergent. shape of the nozzle is determined by the pressure differences on 05 portion as well' as in the convergent port-ion.

opposite sides of the throat. The direct nozzle shownin Fig. 1 is of the so-ca-lled de Laval type and the fluid enters with negligible velocity while the reversed nozzle in the present embodiment depends upon the fluidenteringat a very high velocity... Thus it will be seen that there can be no direct comparison between the two.

In the arran ement described the fluid in passing throng and from this point on the velocity will decrease but the pressure will increase. If the pressure-range for the first or direct nozzle is greater than that corresponding to the maximum efliciency ratio of delivery to supply pressures then it should be first convergent and then divergent, as shown. If that pressure range through which the second or reversed nozzle is to work is greater than that corresponding to said maximum ratio,

it should be firstconvergent and then diver-.

gent. 'For smaller ranges of pressure the form or shape of the nozzles can be suitably modified.

Where the reversed nozzle is first convergentand then diver cut, a certain amount of compression .willta e place 1n the dive ent the portion 2 will have a. relatively low pressure and high'velocity,

Cooling may therefore be desirable while the fluid is passing through the divergent 0rtion. In other words, it may be desirab e to continue the cooling passage up to beyond the point 3. The cooling of the motive fluid may be ucconiplisl'ied in any desired manner and at any suitable point in its passage through the 'intern'iediate chamber or )ortion 2 and the second nozzle. The cooling may take place partly in the intermediate chamber and partly in the second nozzle, or wholly in the chamber or wholly in the nozzle. made in a. variety of ways to adapt it to the conditions of service. tion which has a certain definite length with cylindrical walls forming a non-expanding passage, or it may have walls suitabl shaped to form an expanding or to form a ivergent passage.

The action of the nozzle may be rendered clearer by consideration of a case in which in the initial stage air is taken at atmospheric temperature and pressure. This air is heated and introduced into the first nozzle, and there the pressure or a certain portion of it is converted into velocity and later this velocity is reconverted into pressure and at the same time the air or gas is cooled. This cooling somewhat reduces the volume of the gas while the pressure is raised somewhat above the initial. The loss in heat accounts for the energy expended in producing the increased pressure of the gas.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention,-together with the apparatus which I now consider to represent the best means for carrying it out, but I desire to have it understood that the apparatus shown is only illustrative, and

that the invention can be carried out by other means.

- What I claim as new and desire tosecure by Letters Patent of the United States, is:

1. The method which consists in taking a supply of relatively hot gas under pressure It may have a por-- at low velocity, increasing the velocity and kinetic energy of the gas by ex ansion under suitable conditions, then cool in the gas,

and utilizing the energy so obtaine to com- 1 press the gas ,to' a desired pressure by discharging it at the high velocity. dueto the previous ex ansion'and cooling under. such conditions t at more or less of its energy. oi

pressure, substan velocity is converted into tially as described.

2. The method for compressing gas by the utilization of its own heat energy which consists in allowing it to expand and thus develop velocity and kinetic ener izin its kinetic energy thus evelolped to per. onn the work of compressing t t rough thejdirect conversion of velocity mto pressure, reducing the amount of worknecessary and utilfor efiectin compression of the as b ab stractio'n o heat from it so that its kinetic energy may suflice'to bring it to a pressure higher thanits initial pressure.

3. A nozzle comprisi divergent and convergent portions in the ormer of which gas is expanded without substantial decrease of energy and-in the latter ofuwhich it is recompressed, with means for cooling the gas after it passes'thjrough the first portion of the nozzle.

4. In combination, a nozzle arranged to receive an elasticfluid andconvert pressure of the fluid into velocity as it flows thro h it, a second nozzle receiving fluid .from t e first for converting velocity into ressure'as it flows through it, and a means or cooling the fluid after it .flows into the first-men- A tioned nozzle;

5. A staged compressor comprising a number of nozzles arm inseries, each of which converts the pressure of the fluid into velocityand reconverts it into pressure and comprises means for reduclng the volume of t e fluid by abstraction of heat, with chambers situated between and communicatwith the preceding and succeeding nozz es.

6. A staged compressor comprising a number of nozzles arranged in senes, which first convert'the pressure of the fluid into velocity and reconvert it into pre sure, means for the fluid at some po' 'tion of its pascooling sage t rough the nozzles, ar (1 chambers site uated between and communi eating with the preceding and succeeding n( zzles. I r

7 In a compressor using 1 16111; as a motive power, the combination of a neans which re ceives .the heated fluid and e xpands it, a deit'into velocity as the fluid 'flows tl rough said nozzle, a reversed nozzle which receives the fluid at highvelocity from be direct nozzle and converts'its energy of v1 locity into pressure as the fluid flows through said reversed nozzle, and means for coolil g the fluid during its flow from the direci nozzle into the reversed nozzle and in said reversed nozzle.

In witness whereof I llll ve hereunto set my hand this second day of February, 1906.

u KARL AHLQUIST. Witnesses:

F. SAmninsoN, C. G. Sumner. 

